Schools were closed and the number of cars permitted to move around the city cut by half, while crop sprayers soared over the city centre in an effort to thin the aerial mush.

Once an hour, make an effort to return to the still-point in the centre of the whirlwind of thoughts, emotions and sensations.

Perhaps in an effort to prod a somnolent, introspective Congress into action, he makes the dramatic claim that failure could mean America "would forfeit its seat at the centre of the global economy".